Being a loop while and a for that rotate the same number of times, which is faster? Example:
while :
int i = 0;
int max = 10;
while(i<max){
funcao();
i++;
}
for :
int i;
int max = 10;
for(i=0; i<max; i++){
funcao();
}
Most compilers will produce identical codes and there will be no difference, but only testing on the specific version of a compiler to know. Here's the hint to do and find out for yourself.
Code example generated for for :
40047f: c7 45 f4 00 00 00 00 movl $0x0,-0xc(%rbp)
400486: eb 0a jmp 400492 <main+0x1e>
400488: 8b 45 f4 mov -0xc(%rbp),%eax
40048b: 01 45 fc add %eax,-0x4(%rbp)
40048e: 83 45 f4 01 addl $0x1,-0xc(%rbp)
400492: 83 7d f4 09 cmpl $0x9,-0xc(%rbp)
400496: 7e f0 jle 400488 <main+0x14>
Code example generated for while :
400498: c7 45 f8 00 00 00 00 movl $0x0,-0x8(%rbp)
40049f: eb 0a jmp 4004ab <main+0x37>
4004a1: 8b 45 f8 mov -0x8(%rbp),%eax
4004a4: 01 45 fc add %eax,-0x4(%rbp)
4004a7: 83 45 f8 01 addl $0x1,-0x8(%rbp)
4004ab: 83 7d f8 09 cmpl $0x9,-0x8(%rbp)
4004af: 7e f0 jle 4004a1 <main+0x2d>
Font .
That is, the result is the same in this case.
The differences - to be - are not significant, even for a large number of data. The choice between one structure and another is more about a programmer style and / or readability of the code than about performance issues. The most practical way to gauge the performance gap is by always timing the execution and doing a simple statistical analysis. If anyone considers it important, I can do this and add to this answer.
While looks for True or False . Already For it has to do a comparison with values.
While ends up being "faster".