binary.c

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/**************************************************************************** * binary.c * * Computer Science 50 * David J. Malan * * Displays a number in binary. * * Demonstrates bitwise operators. ***************************************************************************/ #include #include int main(void) { // prompt user for number int n; do { printf("Non-negative integer please: "); n = GetInt(); } while (n < 0); // print number in binary for (int i = sizeof(int) * 8 - 1; i >= 0; i--) { int mask = 1 << i; if (n & mask) printf("1"); else printf("0"); } printf("\n"); }

bmp.h

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/**************************************************************************** * bmp.h * * Computer Science 50 * Problem Set 5 * * BMP-related data types based on Microsoft’s own. ***************************************************************************/ #include /* * Common Data Types * * The data types in this section are essentially aliases for C/C++ * primitive data types. * * Adapted from http://msdn.microsoft.com/en-us/library/cc230309(PROT.10).aspx. * See http://en.wikipedia.org/wiki/Stdint.h for more on stdint.h. */ typedef typedef typedef typedef

uint8_t uint32_t int32_t uint16_t

BYTE; DWORD; LONG; WORD;

/* * BITMAPFILEHEADER * * The BITMAPFILEHEADER structure contains information about the type, size, * and layout of a file that contains a DIB [device-independent bitmap]. * * Adapted from http://msdn.microsoft.com/en-us/library/dd183374(VS.85).aspx. */ typedef struct { WORD bfType; DWORD bfSize; WORD bfReserved1; WORD bfReserved2; DWORD bfOffBits; } __attribute__((__packed__)) BITMAPFILEHEADER; /* * BITMAPINFOHEADER * * The BITMAPINFOHEADER structure contains information about the * dimensions and color format of a DIB [device-independent bitmap]. * * Adapted from http://msdn.microsoft.com/en-us/library/dd183376(VS.85).aspx. */ typedef struct { DWORD biSize; LONG biWidth; LONG biHeight; WORD biPlanes; WORD biBitCount;

bmp.h lectures/7/src/ 65: 66: 67: 68: 69: 70: 71: 72: 73: 74: 75: 76: 77: 78: 79: 80: 81: 82: 83: 84: 85: 86: 87: 88: 89: 90:

DWORD biCompression; DWORD biSizeImage; LONG biXPelsPerMeter; LONG biYPelsPerMeter; DWORD biClrUsed; DWORD biClrImportant; } __attribute__((__packed__)) BITMAPINFOHEADER; /* * RGBTRIPLE * * This structure describes a color consisting of relative intensities of * red, green, and blue. * * Adapted from http://msdn.microsoft.com/en-us/library/aa922590.aspx. */ typedef struct { BYTE rgbtBlue; BYTE rgbtGreen; BYTE rgbtRed; } __attribute__((__packed__)) RGBTRIPLE;

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endian.c

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/**************************************************************************** * endian.c * * Computer Science 50 * David J. Malan * * Reads bf.bfSize from a BMP. * * Demonstrates endianness. ***************************************************************************/ #include #include #include int main(int argc, char *argv[]) { // ensure proper usage if (argc != 2) return 1; // open file FILE *fp = fopen(argv[1], "r"); if (fp == NULL) return 1; // seek to BITMAPFILEHEADER’s bfSize fseek(fp, 2, SEEK_SET); // read in BITMAPFILEHEADER’s bfSize uint32_t bfSize; fread(&bfSize, sizeof(bfSize), 1, fp); // print bfSize printf("\nbfSize: %d\n\n", bfSize); // return to start of file rewind(fp); // read in BITMAPFILEHEADER’s raw bytes uint8_t *buffer = malloc(14); fread(buffer, 1, 14, fp); // print field via cast printf("bfSize: %d\n\n", *((uint32_t *) (buffer + 2))); // print individual bytes in decimal printf("bfSize: %d %d %d %d\n", buffer[2], buffer[3], buffer[4], buffer[5]); // print individual bytes in hexadecimal printf("bfSize: 0x%x 0x%x 0x%x 0x%x\n", buffer[2], buffer[3], buffer[4], buffer[5]); // print individual bytes in binary printf("bfSize: "); for (int i = 2; i < 6; i++) { for (int j = 7; j >= 0; j--) { int mask = 1 << j; if (buffer[i] & mask)

endian.c

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lectures/7/src/ 65: 66: 67: 68: 69: 70: 71: 72: 73: 74: }

memory.c

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lectures/7/src/ printf("1"); else printf("0");

} } printf("\n\n"); // that’s all folks return 0;

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/**************************************************************************** * memory.c * * Computer Science 50 * David J. Malan * * Demonstrates memory-related errors. * * problem 1: heap block overrun * problem 2: memory leak -- x not freed * * Adapted from * http://valgrind.org/docs/manual/quick-start.html#quick-start.prepare. ***************************************************************************/ #include void f(void) { int *x = malloc(10 * sizeof(int)); x[10] = 0; } int main(void) { f(); return 0; }

pointers1.c

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/**************************************************************************** * pointers1.c * * Computer Science 50 * David J. Malan * * Prints a string, one character per line. * * Demonstrates strings as arrays. ***************************************************************************/ #include #include #include int main(void) { // prompt user for string printf("String please: "); char *s = GetString(); if (s == NULL) return 1; // print string, one character per line for (int i = 0, n = strlen(s); i < n; i++) printf("%c\n", s[i]); // free string free(s); return 0; }

pointers2.c

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/**************************************************************************** * pointers2.c * * Computer Science 50 * David J. Malan * * Prints a string, one character per line. * * Demonstrates pointer arithmetic. ***************************************************************************/ #include #include #include int main(void) { // prompt user for string printf("String please: "); char *s = GetString(); if (s == NULL) return 1; // print string, one character per line for (int i = 0, n = strlen(s); i < n; i++) printf("%c\n", *(s+i)); // free string free(s); return 0; }

swap2.c

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lectures/7/src/

/**************************************************************************** * swap2.c * * Computer Science 50 * David J. Malan * * Swaps two variables’ values. * * Demonstrates (clever use of) bitwise operators. ***************************************************************************/ #include // function prototype void swap(int *a, int *b); int main(void) { int x = 1; int y = 2; printf("x is %d\n", x); printf("y is %d\n", y); printf("Swapping...\n"); swap(&x, &y); printf("Swapped!\n"); printf("x is %d\n", x); printf("y is %d\n", y); } /* * Swap arguments’ values. */ void swap(int { *a = *b = *a = }

tolower.c

*a, int *b) *a ^ *b; *a ^ *b; *a ^ *b;

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/**************************************************************************** * tolower.c * * Computer Science 50 * David J. Malan * * Converts an uppercase character to lowercase. * * Demonstrates bitwise operators. ***************************************************************************/ #include #include #include int main(void) { // prompt user for an uppercase character char c; do { printf("Uppercase character please: "); c = GetChar(); } while (c < ’A’ || c > ’Z’); // print number in lowercase printf("%c\n", c | 0x20); // that’s all folks return 0; }

toupper.c

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/**************************************************************************** * toupper.c * * Computer Science 50 * David J. Malan * * Converts a lowercase character to uppercase. * * Demonstrates bitwise operators. ***************************************************************************/ #include #include #include int main(void) { // prompt user for a lowercase character char c; do { printf("Lowercase character please: "); c = GetChar(); } while (c < ’a’ || c > ’z’); // print number in lowercase printf("%c\n", c & 0xdf); // that’s all folks return 0; }

uint.c

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/**************************************************************************** * uint.c * * Computer Science 50 * David J. Malan * * Prints a signed 8-bit integer and an unsigned 8-bit integer. * * Demonstrates signed, fixed-width types. ***************************************************************************/ #include #include int main(void) { // declare and print signed 8-bit integer int8_t i = 0xff; printf("%d\n", i); // declare and print signed 8-bit integer uint8_t u = 0xff; printf("%d\n", u); }

binary.c 1/1 bmp.h 1/2 - CS50 CDN

4: * Computer Science 50. 5: * David J. Malan. 6: * ... 32: * The BITMAPFILEHEADER structure contains information about the type, size,. 33: * and layout of a file ...
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