38 lines
816 B
C
38 lines
816 B
C
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#include "stdio.h"
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#include "string.h"
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int string_to_integer(char *s,int length){
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if (length>1)
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{
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return s[0]=='-'?string_to_integer(s,length-1)*10-(s[length-1]-'0'):string_to_integer(s,length-1)*10+s[length-1]-'0';
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}else{
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return s[0]=='-'?-1/10:s[0]-'0';
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}
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}
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/* 问题：
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1. s是空字符串
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2. s传参为非数字字符
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3. 超出整数所能表示范围
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*/
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int main(){
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char *s = "4323";
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printf("integer == %d\n",string_to_integer(s,strlen(s)) );
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printf("integer == %d\n",string_to_integer("12342",5));
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printf("integer == %d\n",string_to_integer("-11",3) );
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printf("integer == %d\n",string_to_integer("-5",2) );
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printf("integer == %d\n", string_to_integer("3",1));
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printf("integer == %d\n", string_to_integer("abcd",4));
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printf("integer == %d\n", string_to_integer("a",1));
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return 0;
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}
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