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1.1 ! root 1: ! 2: ! 3: abs() General Function abs() ! 4: ! 5: ! 6: ! 7: ! 8: Return the absolute value of an integer ! 9: ! 10: iinntt aabbss(_n) iinntt _n; ! 11: ! 12: abs returns the absolute value of integer _n. The _a_b_s_o_l_u_t_e _v_a_l_u_e ! 13: of a number is its distance from zero. This is _n if _n>=00, and -_n ! 14: otherwise. ! 15: ! 16: ***** Example ***** ! 17: ! 18: This example prompts for a number, and returns its absolute ! 19: value. ! 20: ! 21: ! 22: #include <ctype.h> ! 23: #include <stdio.h> ! 24: ! 25: ! 26: ! 27: main() ! 28: { ! 29: extern char *gets(); ! 30: extern int atoi(); ! 31: char string[64]; ! 32: int counter; ! 33: int input; ! 34: ! 35: ! 36: ! 37: printf("Enter an integer: "); ! 38: fflush(stdout); ! 39: gets(string); ! 40: ! 41: ! 42: ! 43: for (counter=0; counter < strlen(string); counter++) { ! 44: input = string[counter]; ! 45: ! 46: ! 47: ! 48: if (!isascii(input)) { ! 49: fprintf(stderr, ! 50: "%s is not ASCII\n", string); ! 51: exit(1); ! 52: } ! 53: ! 54: ! 55: ! 56: if (!isdigit(input)) ! 57: if (input != '-' || counter != 0) { ! 58: fprintf(stderr, ! 59: "%s is not a number\n", string); ! 60: exit(1); ! 61: } ! 62: ! 63: ! 64: COHERENT Lexicon Page 1 ! 65: ! 66: ! 67: ! 68: ! 69: abs() General Function abs() ! 70: ! 71: ! 72: ! 73: } ! 74: ! 75: ! 76: ! 77: input = atoi(string); ! 78: printf("abs(%d) is %d\n", input, abs(input)); ! 79: exit(0); ! 80: } ! 81: ! 82: ! 83: ***** See Also ***** ! 84: ! 85: fabs(), floor(), general functions, int ! 86: ! 87: ***** Notes ***** ! 88: ! 89: On two's complement machines, the aabbss of the most negative in- ! 90: teger is itself. ! 91: ! 92: ! 93: ! 94: ! 95: ! 96: ! 97: ! 98: ! 99: ! 100: ! 101: ! 102: ! 103: ! 104: ! 105: ! 106: ! 107: ! 108: ! 109: ! 110: ! 111: ! 112: ! 113: ! 114: ! 115: ! 116: ! 117: ! 118: ! 119: ! 120: ! 121: ! 122: ! 123: ! 124: ! 125: ! 126: ! 127: ! 128: ! 129: ! 130: COHERENT Lexicon Page 2 ! 131: ! 132:
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