【c語言】編寫一個函數，將一個數字字串轉換成該字串對應的數字（包括正整數、負整數）

標籤：帶符號字串轉換成整數

/*編寫一個函數，將一個數字字串轉換成該字串對應的數字（包括正整數、負整數）例如："12"  返回12 "-123" 返回-123函數原型：int my_atoi(char *str)*/#include <stdio.h>int my_atoi(char const *str){int sum = 0;int p;int n = 0;if( *str == '-' ){n = 1;str++;}while( *str != '\0' ){ if( *( str ) >= '0' && *( str ) <= '9' ){p = ( int )( *str ) - 48; sum = sum * 10 + p;str++;}}if( n == 1 ){sum = - sum;}return sum;}int main(){    char *p = "-123";printf("轉換後為：%d\n",my_atoi(p));return 0;}<img src="http://img.blog.csdn.net/20150402125124836?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvemhhb3lhcWlhbjU1Mg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" /><img src="http://img.blog.csdn.net/20150402125224316?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvemhhb3lhcWlhbjU1Mg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

【c語言】編寫一個函數，將一個數字字串轉換成該字串對應的數字（包括正整數、負整數）