Style is an extremely broad concept that includes melody, harmony, rhythm, structure, orchestration, etc. There are not clean definitions of style, but more or less specific descriptions that describe groups of music — groupings that become fuzzy the closer one looks, because within those groups, any subgroup of pieces may have certain differentiating characteristics from each other and certain characteristics associating any one piece with some other style.
Even taking just the 1950s as an example, there was serialism, indeterminate music, rock-n-roll, country, Indian classical, Gamelan, Catholic liturgical, Lutheran hymns, gospel, rhythm and blues, Delta blues, Chicago blues, bebop, post-bop, free jazz, cool jazz, bubble-gum pop, folk, bossa nova, etc. And all of these had elements in common with the others. For example, certain indeterminate pieces are largely indistinguishable from free jazz at the level of performance, and the difference might only be who created the piece and whether they're considered a classical or jazz musician — a rather arbitrary way to define style.
In short, one can't give examples of "the 50s style". The question would have to be more specific: "What constitutes the general style of 1950s Billboard Top 40 songs?" And even that is immediately going to run into trouble. So, perhaps: "What characteristics are most commonly associated with the greatest hits of the 1950s?" Well, here are the year-end top hits of 1955 according to Billboard:1
- "Cherry Pink And Apple Blossom White", Perez Prado (YouTube)
- "Rock Around the Clock", Bill Haley & His Comets (YouTube)
- "The Yellow Rose of Texas", Mitch Miller (YouTube)
- "Autumn Leaves", Roger Williams (YouTube)
Based on the diversity of music just in those four, I think anyone would be hard pressed to discern a unifying 1950s style, or even a 1955 style.
Style is slippery.